Industrial truck



July 14, 1953 G. L. TURNER INDUSTRIAL TRUCK 4 Sheets-Sheet 1 Filed July 28, 1950 INVENTOR. GEORGE L. TURNER ATTYS.

July 14, 1953 G. L TURNER INDUSTRIAL TRUCK 4 Sheets-Sheet 2 Filed July 28, 1950 FIG. 2

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ATTYS.

July 14, 1953 s. L. TURNER mnuswam. TRUCK 4 Sheets-Sheet 3 Filed July 28, 1950 INVENTOR. GEORGE TURNER fl nwo,

FIG. 3

July 14, 1953 cs. L. TURNER INDUSTRIAL TRUCK 4 Sheets-Sheet 4 Filed July 28, 1950 FIG. 5

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truck cautiously due to the Patented July 14, 1953 INDUSTRIAL TRUCK George L. Turner, Buchanan, Mich., assignor to Clark Equipment Company, Buchanan, Mich., a corporation of Michigan Application July as, 1950, Serial No. 176,377

12 Claims.

My invention relates generally to industrial trucks and, more specifically, is directed to a mast construction for industrial trucks.

Present mast constructions for use with industrial trucks generally comprise a pair of vertical- 1y extending telescopic assemblies, each comprising a pair of telescopic C-shaped channel members, one of which is adapted to be mounted in fixed relation on the main frame of the industrial truck and the other of which is movable relative to the one channel member. The movable channel members are connected at their upper ends by a crosshead which carries a pair of sprocket gears. Disposed between the pair of telescopic assemblies is a vertically extending hydraulic piston and cylinder assembly which is fixed at its lower end to the main frame of the truck and at its upper end is fixed to the crosshead for effecting movement of the latter and the movable channel members. Guided for vertical movement in the movable channel members is a load supporting carriage to whichthe one ends of a pair of chains are fixed. The chains are trained over the sprocket gears and are fixed at their other ends to the fixed channel members. Vertical movement of the crosshead and movable channel members, through the chains, effects a corresponding vertical movement of the load supporting carriage. While this mast construction has proven satisfactory from a mechanical operation standpoint, it has proven quite unsatisfactory from a safety standpoint. That is, since the hydraulic piston and cylinder assembly for effecting movement of the load supporting carriage is disposed between the pair of'telescopic assemblies, it is directly in front of and in line with the operator of the industrial truck, thus partially obscuring his vision and producing a blind spot. This is not only hazardous, but also decreases the speed with which the truck can be maneuvered, since the'operator must operate the blind spot directly in front of him. i

It is an object of my present invention to provide a mast construction for use with an industrial truck which will not obscure the operators vision directly in front of the truck.

In the preferred embodiment of my present invention, I contemplate the provision of a forward pair of vertically extending piston and cylinder assemblies in which the pistons are adapted to be mounted in fixed relation, With respect to the main frame of the truck, and in which the cylinders are movable relative to the pistons; I further contemplate the provision of a rear pair of vertically extending piston and cylinder asseinblies in which the cylinders are adapted to be mounted in fixed relation to the main frame of the truck and inwhichthe pistons are movable relative to "the cylinders. cro's'she'adis provided for connecting the upper ends of the I cylinders of the forward pair of piston and cylinder assemblies and the upper ends of the piston rods of the pistons of the rear pair of piston and cylinder assemblies. The crosshead is adapted to carry a pair of sprocket gears. A load supporting carriage is slidably mounted on the cylinders of the forward pair of piston and cylinder assemblies and a pair of chains are fixed at their one ends to the load supporting carriage. The chains are trained over the sprocket'gears and are fixed at their other ends to the cylinders of the rear pair of piston and cylinder assemblies. When fluid is admitted to the cylinders of the front and rear piston and cylinder assemblies, the cross'head is raised which, through thechains, causes upward movement of the load supporting carriage. The load supporting carriage is lowered by bleeding the fluid from the cylinders of the front and rear piston and cylinder assemblies. It will be apparent, from the above description, that I have provided a mast construction for use with an industrial truck which will not obscure the operator's vision directly in front of the truck, since I have eliminated the conventional centrally located vertically extending hydraulic piston and cylinder assembly.

While I have described the mast construction as comprising four piston and cylinder assemblies, it will be understood that either a greater or lesser number may be employed, depending on the load carrying capacity of the mast desired. I also do not wish to be limited to fluid actuated piston and cylindler assemblies, as obviously other forms of prime movers may be used as long as they are disposed within the confines of each piston and cylinder assembly.

Now, in order to acquaint those skilled in the art with the manner of constructing and using the devices of my present invention, I shall describe in connection with the accompanying (tirawingsa preferred embodiment of my invenion.

In the drawings:

Figure l is a side elevational view of an industrial truck incorporating the mast construction of my present invention;

Figure 2 is aplan view of the industrial truck and mast construction shown in Figure 1;

Figure 3 is a side elevational view of the mast construction of Figure 1 in a retracted. position;

Figure 4 is a rear elevational view of the mast construction of Figure 3 in an intermediate extended position; and

Figure 5 is a side elevational view of a portion of the mast construction of Figure 3 in an intermediate extended position.

Referring now to the drawings, there is shown an industrial truck, indicated generally by the ref erence numeral II], which comprises a horizontally The pump and motor unit I5 is adapted to'have outlet lines t6 and I1 leading therefrom tQ'fillid operated motors I8 and !9, respectively, these fluid motors being soarranged that fluid'under pressure will operate to impart rotary movement to the pinion shafts 20, extending outwardly therefrom. The pinion shafts project into drive housings 2 I, suitably mounted on the frame ll of, the truck I0, which drive housings 2| support wheel spindles 22. Mounted on the wheel spindles 22, on the outboard side of the drive housings 2|, are drive wheels 23 and 24. Pinions 25 are secured to the outer ends of the pinion shafts 20 and are disposed in meshing engagement with beveled ring gears 26 mounted on the spindles 22 and areadapted to impart rotary movement to the drive wheels 23 and 24.

The main frame ll of the industrial truck II] also provides support for a conventional steering column 21 having a hand steering wheel 28 mounted adjacent the upper end thereof. Disposed closely adjacent the steering column 21 is a drivers seat 29. Suitable control levers 9, illustrated diagrammatically in Figure 2, are disposed closely adjacent the drivers seat 29.

T The steering column 21 has suitable connection to control means whichis adapted to selectively admit fluid to either of the fluid motors 18 or' I9,

individually or conjointly, in the same or in opposite directions for varying the torque delivered to the drive wheels 23 and 24. A caster wheel assembly, indicated generally by the reference numeral 30, is suitably mounted to the main frame I I adjacent the rear end thereof. Since the drive 2 means and control means form no part of my present invention, it is believed that the brief description'will be sufficient for the purposes of the present application.

Ishall'now describe a preferred form of mast construction of my present invention.

Referring'to Figures 3, 4, and 5, there is shown a frame member .3 I which is adapted to be mounted to the main frame H of the industrial truck to, transversely thereof, by spaced bracket 3la. Rigidly mounted to the frame member 3| adjacent each side thereof; are a pair of vertically extending tubular cylinders 32 in which are slidably mounted pistons 33 and piston'rods 33a- The forwardly projecting leg 3 I b of the frame member '3! is adapted to support, adjacent each side thereof, immediately'forward of cylinders 32, a

pair of vertically extending piston rods 34, having pistons 3411, about which are slidahly mounted vertically-extending tubular cylinders 35.

The upper ends of the piston rods 33a and cylinders v35 are interconnected by means of a horizontal crosshead 36, which provides support for a pair of horizontally spaced rotatable sprocket "gear-members. A load supporting carriage, indicated generally at 38, is provided, having spaced vertically extending tubular portions 38a slidably mounted on the cylinders 35. 7 Suitable chains 39 are trained .overthe sprocket gears 31 and have connection adjacent their oneends to the load supporting carriage 38 and at their other ends to.a cross member 40, suitably mounted between the cylinders 32.

The frame member 3| has suitable fluid passageways 3 lo formed therein, which communicate with the interior of the cylinders 32 and, through central openings 341) formed in the piston rods 34, with the interior of the cylinders 35. The fluid'passageways 310 in the frame member 3| are adapted to be selectively placed in communi-, cation with a source of fluid under pressure through a hose line 4 I.

' The mast construction of my present invention is shown in its normal retracted position in Figure 3. When the operator of the truck l0 desires to raise the load supporting carriage 38,'he

need only operate the suitable control lever at 9 which selectively admits fluid under pressure through hose line 4| to the fluid passageways 3|c formed in the frame member 3|. From the passageways 31c fluid is transmitted to the cylinders 32 forcing the pistons 33, together with piston rods 33a, upwardly, and simultaneously fluid is transmitted through the central openings 34b formed in the piston rods 34 to the upper end of the cylinders 35, reacting on the piston 34a, forcing cylinders 35 upwardly. Upward movement of the piston rods 33 and cylinders 35 causes upward movement of the crossheads 36, together with the sprocket gears 31, rotatably mounted thereon. Since the chains 39 are fixed at their one ends to the cross-member 40, the other ends, which are connected to the load supporting carriage 38, are urged upwardly thereby causing the load supporting carriage38 to slide upwardly on the cylinders 35. The mast construction is shown in an intermediate extended position in Figure 4. The load supporting carriage 38 may be lowered by bleeding the fluid from the fluid passageways 3|c in the frame member 3|. From the foregoing description, it will be seen that I have provided a mast construction which will not obscure the operators vision in front of the truck.

As shown in Figures 1 and 2, the load supporting carriage 38 comprises a pair of vertically spaced transversely extending frame members 42 and 43. Pivotally mounted to the upper transverse frame member 42, about a horizontal axis 42a, is a vertically extending load engaging rack 44, which rack 44 is adapted to be pivoted about its horizontal mounting by means .of a centrally located hydraulic piston and cylinder assembly, indicated generally by the reference numeral 45, which comprises a cylinder 46 pivotally mounted to the frame member 3! and a piston rod 41, pivotally mounted to the lower end of the load engaging rack 44.

By selectively operating one of the control levers at 9, fluid under pressure may be admitted to the cylinder 46 of the hydraulic piston and cylinder assembly '45, through fluid lines 60, thereby causing the piston rod 41 to be extended, which, in turn, effects outward movement of the lower end of the load engaging rack 44, causing the latter to pivot about the connection 42a. Upon release of pressure from the cylinder 46, the piston rod 4! is adapted to return to its normal position, as shown in Figure 1, thereby disposing the load engaging rack '44 in a substantially verticalposition. When the load engaging rack 44 is in its normal position, the lower portion thereof is 'adapted'to .abutagainst the lower transverse frame member 4301' the load supporting carriage 38.

Secured to the lower edge of the load engaging rack 44 are a pair of horizontally spaced fork housings 48 which extend lengthwise of the truck [0. Disposed within the fork housings 48 are a pair of fork frames 49 which are adapted to be extended and retracted relative to the fork housings 48 by means of a pair of hydraulic piston and cylinder assemblies, indicated generally by the reference numeral 49, which each comprise cylinders 59 suitably mounted to the fork housings 48 and piston rods 5| pivotally mounted to laterally extending link members 6| secured to the fork frames 49. Upon actuation of the suitable control lever of the group at 9, fluid under pressure is adapted to be admitted, through fluid lines 62, to the closed ends of the cylinders 56 of the hydraulic piston and cylinder assemblies 49. Admission of fluid to the cylinders 59 extends the piston rod 5| rearwardly, thereby causing the fork frames 49 to be retracted inwardly toward the industrial truck I0, relative to the fork housings 48, to the dotted line position shown in Figure 2. Upon admission of fluid under pressure to the opposite ends of the cylinders 59, the piston rods 5| are caused to be retracted inwardly of the cylinders 50, thereby causing the fork frames 49 to be extended away from the industrial truck I9, relative to the fork housings 48, to the solid line position shown in Figure 2. y

While I have described a specific form of load engaging rack and retractable load engaging forks, it will be understood that various other load engaging devices may be secured to the load supporting carriage 38.

While I have shown and described what I believe to be a preferred embodiment of my present invention, it will be understood that various modifications and rearrangements may be made therein without departing from the spirit and scope of my present invention.

I claim:

1. For use with an industrial truck having a main frame, a mast construction comprising, a pair of vertically extending telescopic assemblies each comprising a pair of telescopic elements one of which is adapted to be mounted in fixed relation on said main frame, and the other of which is movable relative to said one element, means for extending said pair of movable elements being disposed within the confines of each telescopic assembly, a load supporting carriage guided for movement solely on one element of each of said telescopic assemblies, and means between said telescopic assemblies and said load supporting carriage for effecting upward movement of the latter when said movable elements are extended.

2. For use with an industrial truck having a main frame, a mast construction comprising, a pair of fluid actuated assemblies each comprising piston and cylinder elements having their lengthwise axes extending substantially vertically, one of said elements being adapted to be mounted in fixed relation on said main frame, and the other element being movable relative to said one element, a load supporting carriage guided for movement on one element of each pair of said fluid actuated assemblies, and means between said fluid actuated assemblies and said load supporting carriage for effecting upward movement of the latter when said movable elements are extended.

3. For use with an industrial truck having a main frame, a mast construction comprising,

a pair of fluid actuated assemblies each comprising piston and cylinder elements having their lengthwise axes extending substantially vertically, one of said elements being adapted to be mounted in fixed relation on said main frame, and the other element being movable relative to said one element, a load supporting carriage guided for movement on said pair of movable elements, and means between said fluid actuated assemblies and said load supporting carriage for effecting upward movement of the latter when said movable elements are extended.

4. For use with an industrial truck having a main frame, a mast construction comprising, a pair of fluid actuated assemblies each comprising piston and cylinder elements having their lengthwise axes extending substantially vertically, one of said elements being adapted to be mounted in fixed relation on said main frame, and the other element being movable relative to said one element, a load supporting carriage guided for movement on said pair of movable elements, and means between said movable elements and said load supporting carriage for effecting upward movement of the latter when said movable elements are extended.

5. For use with an industrial truck having a main frame, a mast construction comprising, a pair of fluid actuated assemblies each comprising piston and cylinder elements having their lengthwise. axes extending substantially vertically, one of said elements being adapted to be mounted in fixed relation on said main frame, and the other element being movable relative to said one element, a load supporting carriage guided for movement on said pair of movable elements, a horizontal crosshead connecting the upper ends of said movable elements, and means carried by said crosshead for effecting upward movement of said load supporting carriage when said movable elements are extended.

6. For use with an industrial truck having a main frame, a mast construction comprising,

a pair of fluid actuated assemblies each comprising piston and cylinder elements having their lengthwise axes extending substantially vertical- 13!, one of said elements being adapted to be mounted in fixed relation on said main frame, and the other element being movable relative to said one element, a load supporting carriage guided for movement on said pair of movable elements, a horizontal crosshead connecting the upper ends of said movableelements, a sprocket gear carried by said crosshead, a chain trained over said sprocket gear and being fixedly mounted at its one end and mounted at its other end to said load supporting carriage.

'7. For use with an industrial truck having a main frame, a mast construction comprising, a pair of fluid actuated assemblies each comprising piston and cylinder elements having their lengthwise axes extending substantially vertically and in which said piston element is adapted to be mounted in fixed relation on said main frame and said cylinder element is movable relative to said piston element, fluid passageways formed in said piston elements and opening into said cylinder elements, said passageways being adapted to be placed in communication with a source of fluid under pressure for effecting movement of said cylinder elements relative to said piston elements, a load supporting carriage guided for movement on said pair of cylinder elements, and means carried by said cylinder elements and having connection with said load supporting a second pair of telescopic elements one disposed rearwardly of each of said first pair of telescopic assemblies, each of said second pair of telescopic assemblies comprising a pair of telescopic elements one of which is adapted to be mounted in fixed relation on said main frame, and the other of which is movable relative to said one element; means for extending said movable elements of said first and second pair of telescopic assemblies being disposed within the confines of each telescopic assembly, a load supporting carriage guided for movement on one element of each of said first pair of telescopic assemblies, and means between said telescopic assemblies and said load supporting carriage for effecting upward movement of the latter when said movable elements of said first and second pair of telescopic assemblies are extended.

9. For use with an industrial truck having a main frame, a mast construction comprising, a first pair of fluid actuated assemblies each comprising piston and cylinder elements having their lengthwise axes extending substantially vertically and in which one of said elements is adapted to be mounted in fixed relation on said main frame, and the other element of which is movable relative to said one element; a second pair of fluid actuated assemblies one disposed rearwardly of each of said first pair of fluid actuated assemblies, each of said fluid actuated assemblies comprising piston and cylinder elements ing carriage for' effecting upward movement of the latter when said movable elements are extended.

l0. For use with an industrial truck having a main frame, a mast construction comprising, a

first pair of fluid actuated assemblies each comprising piston and cylinder elements having their lengthwise axes extending substantially vertically and inwhich said piston elementis adapted to be mounted in fixed relation on said main frame and said cylinder element is movable relative to said piston element; a second pair of fluid wise axes extending substantially vertically and ments of said first pair of fluid actuated assemblies and having connection with said load sup-'- porting means for effecting upward movement of the latter when said cylinder elements of said first pair of fluid actuated assemblies and said piston elements of said second pair of fluid actuated assemblies are extended.

11. For use with an industrial truck having a main frame, a mast construction'comprising, a first pair of fluid actuated assemblies each comprising p Ston and cylinder elements having their lengthwise axes extending substantially vertically and in which said piston element is adapted to be mounted in fixed relation on said main frame and said cylinder element is movable relative to said piston element; a second pair of fluid actuated assemblies one disposed rear-wardly of each of said first pair of fluid actuated assemblies, each of said fluid actuated assemblies comprising piston and cylinder elements having their lengthwise axes extending substantially vertically and in which said cylinder element is adapted to be mounted in fixed relation on said main frame and said piston element is movable relative to said cylinder element; a load supporting carriage guided for movement on said cylinder elements of saidfirst pair of fluid actuated assemblies, a horizontal crosshead connecting the upper ends of said'cylinder elements of said first pair of fluid actuated assemblies and said piston elements of said second pair of fluid actuated assemblies, and means carried by said crosshead for effecting upward movement of said load supporting carriage when said cylinder elements of said first pair of fluid actuated assemblies and said piston elements of said second pair of fluid actuated assemblies are extended.

12. For use with an industrial truck having a' main frame, a mast construction comprising, a

first pair of fluid actuated assemblies each comand said cylinder element is movable relative to said piston element; a second pair of fluid actuated assemblies one disposed rear-wardly of each of said first pair of fluid actuated assemblies, each of said fluid actuated assemblies comprising piston and cylinder elements having their lengthwise axes extending substantially vertically and in which said cylinder element is adapted to be mounted in fixed relation on said main frame and said piston element is movable relative to said cylinder element; a load'supporting carriage guided for movement on said cylinder elements of said first pair of fluid actuated assemblies, a horizontal crosshead connecting the upper ends of said cylinder elements of said first pair of fluid actuated assemblies and said piston elements of said second pair of fluid actuated assemblies, a sprocket gear carried by said crosshead, and a chain trained over said sprocket gear and being fixed at its one end to said cylinder elements of said second pair of fluid actuated assemblies and at its other end to said load supporting carriage.

GEORGE L. TURNER.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Abbe Oct. 24, 1950 Number 

